Blogs / Cosmic Variance

Another summer, another young scientist is elevated from the ranks of Humble Seeker to Wizened Oracle. Or, in more familiar terms, someone successfully gets their Ph.D. The latest elevatee is Lotty Ackerman, my first student here at Caltech. Lotty’s work is well-known to CV readers; she and I collaborated with Mark Wise on the question of a preferred direction in inflation, which was featured in the series of Anatomy of a Paper posts. She also worked with Matt Buckley, Marc Kamionkowski and me on the Dark Photon idea. And she worked with other people on other things, including cosmological density perturbations from reheating and the more experimentally-oriented question of asymmetric beams in the WMAP satellite.

Today Lotty successfully defended her thesis, and we’ll be sad to see her go. But California’s loss is Texas’s gain, as she’ll be taking up a postdoc at the new Texas Cosmology Center in Austin. Best of luck!

Gödel’s Lost Letter writes an interesting post suggesting that complexity classes — categories of computational problems related by the resources necessary to solve them — play a similar role in complexity theory as elementary particles in high-energy physics. (Via Chad.) All very fascinating stuff, no doubt. But along the way a much more important issue is raised: when there is a seminar, should we have donuts before, or after?

Back then, Yale computer science used the post-talk-food normal form. That is after the talk donuts were served to the audience and the speaker. Most places then and now use pre-talk-food normal form, but Yale was different. I always wondered why we were different, but it was Yale.

I have to say that Yale is right on this one, and yet almost everyone does it backwards. Some sort of refreshments — coffee, tea, stale cookies, donuts if you’re lucky — are generally served before a colloquium or seminar, to attract an audience and presumably put people in a good mood. The problem is: we haven’t heard the talk yet, so we can’t chat about that, and if the audience is big enough we might not even know which person is the speaker.

Whereas, if donuts or whatever are served after the talk, not only do you make it more awkward for grad students to scarf some food without sitting through the seminar, but you have offered a very natural topic of conversation — the substance of the actual talk everyone has just heard. And the resulting conversation will usually be better than the desultory Q&A that follows a typical talk. For one thing, it’s just more natural to stand around and chat while sipping coffee or munching a donut than while one person stands at the front of a room and everyone else sits in the crowd (many of whom are restless and ready to scat). For another, students who might be intimidated out of asking a question in front of the whole audience can screw up their courage in a more informal setting. And most importantly, the chances that the actual speaker will get something intellectually useful out of the whole experience are enormously larger if they get to interact with a bunch of people who have just heard their talk. (Not even to mention the abomination of the usual “lunch talk,” where the undernourished speaker seminars away in front of a collection of people happily chewing away at their meals.)

I’m sure a lot of influential people read this blog. Let’s put that power to good use. What do we have to do to change the traditions and make it standard that coffee is served after the talk instead of before?

Last week, members of the Caltech community received a dreaded piece of email: a student had taken their own life. The tragedy was compounded by the fact that this was the third Caltech student to do so in the last year.

Suicide is the second-leading cause of death among college students. In the aftermath of such an event, there is a feeling of powerlessness; you try to console or sympathize with anyone who might have known the student, but at the end of the day there’s no much you can do. But it is possible to take some steps to try to prevent such tragedies from happening.

It is believed that, in over 80 percent of cases, people who attempt suicide are struggling with some form of mental illness, such as depression, bipolar disorder, or schizophrenia. Although there is no way to know for sure whether someone is contemplating such a drastic step, there are certain warning signs, including severe depression and changes in mood or habits. Caltech has set up a website on preventing suicide and violence, which goes over some of the signs and ways that a friend can take steps to help persuade someone from going too far:

• http://www.counseling.caltech.edu/safetynet.html

I’m sure that many universities (and companies) have similar resources; it’s worth taking a minute to familiarize yourself with what’s available where you work or go to school.

Most importantly, if you’ve ever contemplated suicide yourself: don’t do it. That’s cheap and easy advice, but the crucial point is to make sure you stop, talk to people, and take advantage of counselors. Being a college student can be an extraordinarily stressful and pressure-filled time; if you’re feeling overwhelmed, be assured that it’s not just you, and that it is possible to get through it. You will find people who are willing to listen, understand, and try to be helpful, if you are willing to reach out to them. Tough times can be overcome, but taking a life is irrevocable. Seek help before the pressure gets to be too much.

Here at Cosmic Variance we love our teaching moments. Science is everywhere, and there’s no need to be stuffy about it. One of the best ways to communicate the excitement that we feel about science to a much wider audience is to connect it to popular culture in all sorts of ways — whether it’s Buffy the Vampire Slayer, NUMB3RS, or Angels & Demons.

So it’s great to see the producers of ABC’s hit TV show LOST jump on the bandwagon. This fall they will be releasing the DVD collection of the fifth season, and the Blu-ray edition is going to feature a special treat: mini-”lessons” on various academic subjects related to the show. (The final season of the show begins early in 2010.) One of those subjects is time travel, and you have a pretty esteemed group of professors guiding you through this fascinating subject: Nick Warner of USC (who taught me general relativity back in the day), our old friend Clifford Johnson, and myself. Suffice it to say, I’ve seen the rough cut, and they did a good job — and we had quite a bit of fun. I was only included because having all the professors speak with British accents would have seemed a bit posh.

And along with that, they’ve just launched an associated website: LOST University. You can see what the other courses in the curriculum are going to be, including Philosophy and Foreign Languages. At the moment the website is essentially promotion for the DVD’s themselves, but I’m hoping more content will appear over time. LOST has a tradition of enhancing the show with quite elaborate online activities, in the form of alternate reality games. So hopefully this new site won’t simply be an advertisement — one of the lessons of new media is that giving away cool stuff for free makes it more likely that people will pay money for the even cooler stuff.

To be clear: the science of time travel on LOST does not necessarily obey all the rules. None of us had anything to do with the show itself, and I have no idea what the writers did in terms of seeking science advice. But understanding how the rules are broken can serve as fodder for teaching moments just as easily as seeing them obeyed. That’s life here “on the cutting edge of tomorrow.”

In the Fall I’ll be starting teaching again, after a semester away on sabbatical and then enjoying teaching relief during my first semester at Penn. I’ll be teaching a course that I truly love, and that I’ve taught a number of times before – Mathematical Methods of Physics I, to a class of beginning graduate students, and some interested seniors.

The backbone of this course, as I teach it, is rather traditional, since the topics involved are things that form the basis of the toolbox that professional physicists need. From year to year I have added various extra topics (some differential geometry, some topology, some group theory, …), but I always cover

• Analysis of Complex Functions
• Exact and Approximate Evaluation of Sums and Integrals
• Exact and Approximate Solution of Ordinary Differential Equations
• Transform Calculus
• Sturm-Liouville Theory
• The Calculus of Variations

One challenge in a course like this is to maintain the connection with actual applications of the techniques one is covering. Since I was originally taught this material in a set of courses as a mathematics undergraduate, my own take on the material can be rather formal, and I have worked over the years to balance this out. However, as you might guess, my own examples are predominantly drawn from those areas of physics with which I am most familiar – for example, supersymmetry, and the restrictions that holomorphy places on superpotentials, is a nice illustration of the power of complex analysis.

But this course is supposed to provide a basis for all graduate students, including those with interests in other branches of theoretical physics or, indeed, experimental physics or observational astrophysics and cosmology. There are, of course, rather general things that one can do that should be of use to everyone, such as the use of Fourier and Laplace transforms in solving heat, diffusion, and other equations. And the calculus of variations appears everywhere already. There are also, incidentally, lots of cute things one can do in the opposite direction, like cooking up examples of oscillating systems in which the sum over all modes gives the total energy, which is easy to calculate another way, and using this to provide a way to compute infinite sums. Nevertheless, what I really yearn for are even more examples illustrating the use of some of the above topics from other branches of physics.

I could, of course, annoy my colleagues with this question, but I thought that opening it up to Cosmic Variance readers might provide some novel suggestions. So, if you have some unusual example, brief enough to be useful in a class, of the use of any of the above in any branch of physics (even particle physics and cosmology – there’s plenty I don’t know there also), I’d appreciate you filling me in in the comments.

And if any of my students-to-be are reading this – beware; it’s possible that good suggestions you see here, that don’t make it into class, may turn up on exams – who knows?

Via Dmitry Podolsky, a series of YouTube videos from Stanford encompassing an entire course by Lenny Susskind on general relativity. I didn’t look closely enough to figure out exactly what level the lectures are pitched at, but it looks like a fairly standard advanced-undergrad or beginning-grad introduction to the subject. (For which I could recommend an excellent textbook, if you’re interested.) This is the first lecture; there are more.

It’s fantastic that Stanford is giving this away. I don’t worry that it will replace the conventional university. The right distinction is not “people who would physically go to the lectures” vs. “people who will just watch the videos”; it’s between “people who can watch the videos” and “people who have no access to lectures like this.” And Susskind is a great lecturer.

All the signs are pointing to a major announcement by the University of California, possibly as early as tomorrow, in response to the large cuts in state funding in its next fiscal year, which begins July 1. The UC total budget of $19 billion includes core state funding which will be reduced from $3.3 to $2.8 billion, representing a 10% cut in state funding, which was 17% of the total university funding this year. On the table are furloughs, pay cuts, and staff reductions, some mix of which now seems inevitable.

The UC system has ten campuses, centrally administered from the UC Office of the President in Oakland. Earlier this spring the UCOP paved the way for legal authority to enact emergency measures in the face of fiscal emergencies such as this. Every department in the the entire system has been struggling to meet large budget reductions already, but the demise of the state ballot Propositions 1a and 1b meant that the reductions for the 2009/10 year were greater than hoped.

Then, on Friday, UC president Mark Yudof announced a 5% pay cut for senior management, down to the level of Vice Chancellors at each campus. It therefore seems rather likely that a general 5% reduction in some form is in the offing. The 23-campus California State University system faces a similar situation.

Overall, this is not that bad when you consider the fact that 235,000 California state workers will face a 14% pay reduction, and the the US economy as a whole is still shedding well over half a million jobs per month. But then, as the Chronicle of Higher Education asks, will higher education be the next bubble to burst?

It has become somewhat of a tradition here at CV to announce our newly-minted PhDs. It is thus with great pleasure that I congratulate Devdeep Sarkar on having earned his degree in Physics from the University of California, Irvine, co-advised by Asantha Cooray and myself. Devdeep has worked very hard over the past few years, producing a total of 7 papers:

A. G. Riess et al.; Astrophys. J. (2009; in press)
A Redetermination of the Hubble Constant with the Hubble Space Telescope from a Differential Distance Ladder

D. Sarkar et al.; Astrophys. J. Lett. 684 L13 (2008)
Implications of Two Type Ia Supernova Populations for Cosmological Measurements

A. Cooray, D. Sarkar, and P. Serra; Phys. Rev. D 77 123006 (2008)
Weak Lensing of the Primary CMB Bispectrum

D. Sarkar et al.; Phys. Rev. D 77 103515 (2008)
Cosmic Shear from Scalar-Induced Gravitational Waves

D. Sarkar et al.; Astrophys. J. 678 1 (2008)
Lensing and Supernovae: Quantifying the Bias on Dark Energy Equation of State

D. Sarkar et al.; Phys. Rev. Lett. 100 241302 (2008)
Beyond Two Dark Energy Parameters

D. Sarkar, H. Feldman, and R. Watkins; Mon. Not. R. Astron. Soc. 375 691 (2007)
Bulk flows from velocity field surveys: A Consistency Check

Much of Devdeep’s work has focused on gravitational lensing (of CMB and of supernovae), as well as a better way to analyze data to constrain dark energy (in redshift bins, instead of using arbitrary, poorly-motivated parameterizations). Next month Devdeep is fortunate to be starting a postdoc with Dragan Huterer at the MCTP at Michigan.

Congratulations to Dr. Sarkar on a well-earned piece of parchment!

Via Brad DeLong, an article by Kevin Carey in the Chronicle of Higher Education starts with the obvious — the internet is killing newspapers as we knew them — and asks whether the same will happen to universities.

Much of what’s happening was predicted in the mid-1990s, when the World Wide Web burst onto the public consciousness. But people were also saying a lot of retrospectively ludicrous Internet-related things — e.g., that the business cycle had been abolished, and that vast profits could be made selling pet food online. Newspapers emerged from the dot-com bubble relatively unscathed and probably felt pretty good about their future. Now it turns out that the Internet bomb was real — it just had a 15-year fuse.

Universities were also subject to a lot of fevered speculation back then. In 1997 the legendary management consultant Peter Drucker said, “Thirty years from now, the big university campuses will be relics…. Such totally uncontrollable expenditures, without any visible improvement in either the content or the quality of education, means that the system is rapidly becoming untenable.” Twelve years later, universities are bursting with customers, bigger, and (until recently) richer than ever before.

But universities have their own weak point, their own vulnerable cash cow: lower-division undergraduate education. The math is pretty simple: Multiply an institution’s average net tuition (plus any state subsidies) by the number of students (say, 200) in a freshman lecture course. Subtract whatever the beleaguered adjunct lecturer teaching the course is being paid. I don’t care what kind of confiscatory indirect-cost multiplier you care to add to that equation, the institution is making a lot of money — which is then used to pay for faculty scholarship, graduate education, administrative salaries, the football coach, and other expensive things that cost more than they bring in.

I’m not sure I buy it. Let’s think about what good purposes a college or university might serve. Off the top of my head, I can think of several:

1. Classroom-based education. Certainly important.
2. Extracurricular learning. This includes everything from “participating in actual academic research” to “serving on the school newspaper.”
3. Meeting different kinds of people. Not only do students get exposed to professors, and an academic way of thinking about problems, but they also meet other students, hopefully from a wide variety of backgrounds.
4. Establishing independence. For many people, going to college is the first time one lives away from home, and begins to establish an identity separate from one’s family.
5. Belonging to a community. From the university itself to numerous smaller subcultures within, college provides an opportunity to belong. As great as the Teaching Company is, it doesn’t have a basketball team in the Final Four.

Feel free to add your own. We can argue whether online learning can be effective in replacing the first of these — after all, hearing a recorded lecture is not the same as hearing it live. But it would appear very difficult to replace the others. The four years one spends at college are often the most formative (and perhaps the most enjoyable) years of one’s life. It’s not clear, of course, how much people are willing to pay for those other purposes, as important as they may be.

On the other hand, there is a long-established bargain at big research universities that could conceivably come unraveled at the hands of the internet. Namely: it is research and scholarship that attracts the faculty and establishes the academic reputation of a school, but it is teaching that brings in students and tuition dollars. This is not an arrangement based entirely on avarice; the top research schools bring in a lot more money from grants and gifts than they do from student tuitions. But it reflects a deep philosophical split, that might signal an underlying instability: from within academia, the purpose of the university is seen as the production of new scholarship; from outside academia, the purpose of universities is seen as the teaching of students.

In the case of newspapers, the internet made it harder to tightly bundle straightforward news with advertising and sections of the paper any one reader might not be interested in. In the case of universities, will the internet make it harder to bundle teaching and research? Quick, name the largest private university in the U.S. The answer is the University of Phoenix, founded in 1976, where 95% of faculty are part-time and the large majority of teaching happens completely online.

It could happen that more education-providing corporations (one hesitates to call them “universities”) could develop better ways to provide online classroom educations to a large number of students who are interested in the first purpose listed above but are unwilling to pay for the second. If that model catches on, it will cause dramatic upheaval in the economy of traditional universities. And, much as I love the internet, that would be too bad.

Wednesday was a big day in the physics department at Penn, as we held the annual Henry Primakoff lecture. Primakoff was the first Donner Professor of Physics at Penn, and served on the faculty from 1960 onwards. He was best known for his eponymous effect, which, among other things, describes the production of neutral pseudoscalar mesons by the interaction of a photon with a virtual photon in the Coulomb field of a heavy nucleus. (Intrigued to know more about Primakoff, I came across this touching memoir by the late Peter Rosen, who had worked with him.)

Since T.D. Lee’s inaugural lecture in 1985, a string of outstanding physicists have delivered the Primakoff lecture. But I was extremely lucky that, in my first year here, the honor fell to a cosmologist – Jim Peebles. Jim was nice enough to give an astrophysics seminar yesterday afternoon (on “The Cosmology of Small-Scale Structure”), and then, after an hour break, to give his Primakoff lecture, titled “Finding the Big Bang”.

Popular-level lectures these days often focus on some of the more recent developments in the field, and the reasons they are so exciting. Certainly quite a few of my own public lectures take this approach. But Jim took a different tack, focusing instead on the sequence of events through which the big bang theory became accepted. He gave a wonderful historical account of the discovery of cosmic expansion, and a more personal description of the most important later discoveries; of the microwave background radiation (CMB) and the abundances of the light elements (Big Bang nucleosynthesis – BBN). Jim himself was around for a great deal of this important history (Indeed, it was Jim’s advisor, Bob Dicke, who set David Wilkinson looking for the CMB, only to be serendipitously scooped by Arno Penzias and Bob Wilson), and his take on how the various discoveries were made, and who played the important roles taught me quite a few details that I hadn’t realized. I don’t think I can do real justice to his account, but fortunately I don’t have to, since all will be described in an upcoming book, edited by Jim, with Bruce Partridge and Lyman Page, coming out at the end of next month. I’m sure we’ll write about it here.

That evening, I turned up for the dinner to celebrate the Primakoff lecture to find out that I was the second person to arrive, the first being Mildred Cohn Primakoff. Being new to Penn, I didn’t know that Mildred was around, and it was a wonderful surprise to meet her. Ms. Primakoff was born in 1913, and became a successful female scientist at a time when that was far less common than today, becoming the Benjamin Rush Professor of Physiological Chemistry at Penn, and receiving the National Medal of Science. They must have made quite a remarkable couple!